UNBELIEVABLE: Afghan War Rules Leave U.S. Troops Wondering When It’s OK to Shoot

U.S. is no longer at war with Taliban, so Special Forces remaining in Afghanistan have to weigh every situation to decide whether striking them is justified

U.S. spy drones had no trouble spotting the Taliban fighters. There were more than 20 figures snaking through sparsely wooded hills, trying to outflank the Afghan government commandos in the village below.

In the starry darkness overhead, American helicopters loitered armed with precision-guided missiles, along with a flying gunship capable of drenching the area with cannon-fire. It would have been a hard shot to miss.

But before they could fire, the Americans knew they would have to get past the lawyers.

In the amorphous twilight of the Afghan war, it isn’t enough to draw a bead on the enemy. Before they shoot, U.S. troops have to navigate a tricky legal and political question: When is it OK for them to kill Taliban?

The operation late last month in Elbak, a flyspeck village in Kandahar province, exposed the complexity of implementing President Barack Obama’s Afghan strategy in the mud-brick villages, steep mountains and vast poppy fields where the combat takes place. With their Afghan allies walking into a possible ambush that night, U.S. commanders, monitoring video feeds and radio traffic miles from the front, had to judge whether enemy fighters who weren’t actually fighting constituted an imminent threat.

Mr. Obama, who campaigned on a promise to extract the U.S. from its long wars, has declared an end to the American combat mission in Afghanistan and set guidelines for when the remaining 9,800 U.S. troops, many of them in elite special-operations units, may use lethal force.